1. Field of the Invention
The invention relates to a read head assembly for optically reading information on a track of a record member and more particularly to a motor assembly for effecting tracking or focusing adjustment of an optical element of such an assembly.
2. Description of the Prior Art
With the exception of a few examples employing piezoelectric transducer elements or the like, the adjustment of the optical element of an optical read head assembly for tracking or focusing purposes is accomplished by one or more electromagnetic motors, which must be relatively powerful to effect the required rapid movement of the optical element while at the same time being relatively light and compact. To achieve these requirements, it has previously been proposed to employ the principal of providing permanently magnetized motor poles which are strengthened or counteracted by electromagnetic means, as shown, for example, in U.S. Pat. No. 4,479,051, issued on Oct. 23, 1984. Generally, however, such prior art devices have been relatively intricate and expensive for various reasons, including the use of complex or multiple electromagnet coils, the use of one or more moveable coils and the attendant need for flexible connecting wires, close tolerance requirements and structural design features that complicate coil winding or assembly.